High speed data modification system and method

1. A data modifier for modifying a first input stream of datums to produce a first output stream of datums, each datum having one of a plurality of data formats, the plurality of data formats including a frame and a link delimiter, the data modifier comprising: a first trigger subsystem for generating a trigger signal when a first input datum of the first input stream matches a first specified data pattern; and a modification subsystem responsive to the trigger signal, for altering specified portions of the first input datum so as to form a corresponding output datum having a fixed, real-time delay with respect to the first input datum.

2. The data modifier of claim 1, wherein the modification subsystem outputs as output datums unchanged input datums in the absence of trigger signal.

3. The data modifier of claim 1 further comprising: a second trigger subsystem monitoring a second input stream of input datums and generating an arming signal when a second input datum in the second input stream matches a second specified data pattern; and wherein the first trigger subsystem generates the trigger signal in response to the arming signal.

4. The data modifier of claim 1, wherein the specified portions of the first input datum are specified by a sequence of commands, each command specifying a replacement word for a corresponding word in the first input datum.

5. The data modifier of claim 1, wherein the link delimiter format includes a group of link delimiter types; and wherein the first specified data pattern is a one of the group of link delimiter types.

6. The data modifier of claim 1, wherein prior to searching the first input stream for the first datum the first trigger subsystem searches the first input stream for a second input datum matching a second specified data pattern.

7. The data modifier of claim 1, wherein altering specified portions of the first input datum causes the corresponding output datum to be shorter than the first input datum.

8. The data modifier of claim 1, wherein the first input datum is a frame including at least a one of an Start of Frame delimiter (SOF) and an End of Frame delimiter (EOF) and wherein altering the first input datum produces an output datum lacking at least a selected one of the EOF and the SOF.

9. A method of modifying a first input stream of datums to produce a first output stream of datums, each datum of the first output stream corresponding to a one of the datums of the first input stream corresponding datum of the first input stream, each datums having a one of a plurality of data formats, the plurality of data formats including a frame and a link delimiter, the method comprising the steps of: a) generating a trigger signal when a first input datum of the first input stream matches a first specified data pattern; b) modifying the first output stream in response to the trigger signal by altering specified portions of the first input datum so as to form a first output datum corresponding to the first input datum, the first output datum having a fixed, real-time delay with respect to the first input datum.

10. The method of claim 9 further comprising the steps of: c) generating an arming signal when a second input datum in a second input stream of datums matches a second specified data pattern; and d) generating the trigger signal in response to the arming signal.

11. The method of claim 9, wherein the first input datum includes a first Cylical Redundancy Check (CRC); and wherein step b) further comprises: (1) calculating a second CRC for the first output datum after altering the specified portions of the first input datum; and (2) replacing in the first output datum the first CRC with the second CRC.

12. The method of claim 9, wherein the specified portion of the input datum is a first word; and wherein step b) includes replacing the first word with a second word in the first output datum.

13. The method of claim 9, wherein step b) comprises: (1) identifying a first word in the first input datum; (2) applying a mask to the first word to generate a second word; and (3) replacing in the first output datum the first word with the second word.